The founder and General Manager of Bolite Optoelectronics, Dr. Bowen Cheng, was invited to present at the recent Touch Taiwan 2021 Conference in April. The title of his talk was “Laser Processing Applications for the Manufacturing of Mini and MicroLED Displays.” Since it was presented in Mandarin only, microled-info.com caught up with Dr. Cheng to learn more about this trending subject and the company he started.

Q: Dr. Cheng, can you please tell us a little about your background, prior to starting Bolite?

I was a research engineer at Xerox PARC and helped develop surface micromachined microspring interconnects in a project funded by the U.S. Army Research in collaboration with Oracle. I was also a vital member of the team that successfully demonstrated the world's shortest wavelength diode laser at the time, a 250 nm UV laser for military applications. With these experiences in both semiconductor laser processing and MEMS processing, I decided to start Bolite and build a team to develop state-of-the-art laser solutions for microprocessing applications.

Q: I must admit I’ve not heard of Bolite before. What differentiates you from other laser microprocessing companies?

Researchers from Korea's Electronics and Telecommunications Research Institute (ETRI) developed a new process to produce microLED displays, which they say can be highly cost effective.

The new process is based on a novel film-like material developed at ETRI, called SITRAB. Using lasers, the process apparently detaches the microLED from the original epiwafer and bonds it to the SITRAB film in the same process step. The LEDs are then transferred to the final target backplane.

3D-Micromac announced a new microLED mass transfer tool, called microCETI. The company says its new technology can be used to transfer over 130 million microLEDs per hour.

MicroCETI is based on a laser-induced forward transfer (LIFT) process that can support almost any microLED material and shape. The tool also includes optional modules - a laser lift-off (LLO) module, and a single LED die repair module.

Micro-LED and mini-LED developer Rohinni announced that the company has developed a new design for its miniLED composite bondhead, which now allows multiple bondheads to run in parallel. Rohinni says it has been able to accelerate its miniLED deposition speed 14X compared to 'competing technologies'.

With the new system, Rohinni demonstrated >99.999% placement yield and scalability at speeds greater than 100 die per second. 

USA-based eLux was established in 2016 as a spin-off from Sharp Labs of America, to commercialize a unique MicroLED production technology. A year ago we discussed the company's technology and business with its CEO, Jong-Jan Lee.

Today eLux announced that it has installed an automated fluidic assembly tool at its prototype fab in Taiwan. The new tool features fully automatic cassette-to-cassette fluidic assembly of ten display panels, each up to 15-inch in size. The tool has provisions for capture and recycle of microLEDs and assembly fluids to minimize operating costs, and its capacity can be expanded by adding two additional modules.

Global digital signage solution provider STRATACACHE is constructing the first US-based complete display production facility in Eugene, Oregon. The future MicroLED E4 fab is planned to commence production in 2022, and the fab will be a complete microLED production line, from epiwafer (on 300 mm silicon wafers), through transfer process and to final module assembly.

This project is extremely interesting, and we set out to discuss it with STRATACACHE's founder and CEO, Chris Riegel. At STRATACACHE, Chris leads strategic direction, technology development and engineering operations, and the MicroLED fab project seems to be personally spearheaded by him.

Singapore-based electronics assembly solutions provider Kulicke & Soffa announced that it has acquired Uniqarta, a US-based developer of MicroLED placement technology.

Uniqarta developed a unique LED die transfer technology that uses ultra-fast lasers to enable contactless LED de-bonding and placement solution. Uniqarta's technology is branded as Laser-Enabled Advanced Placement, or LEAP).

MicroLED display technology developer X Display Company (XDC) announced that it installed the world's first 300 mm elastomer stamp based mass MicroLED transfer equipment late in 2020. This tool was installed in the US and the company hopes to start shipping several similar tools for its customers later in 2021.

XDC spun out of X-celeprint in 2019 and retained the equipment organization from that transaction. XDC has over 15 years of experience with mass transfer micro printing technologies, and is offering a range of tools for microLED transfer, suitable for R&D work and industrial-scale production.

Canada-based microLED technology developer VueReal announced a partnership with ASM Pacific Technologies (ASMPT) to integrate VueReal's cartridge microLED mass transfer solution into ASMPT's mass transfer bonding solution for microLED display applications.

Vuereal says that this new partnership will allow its customers to achieve 99.99+% transfer yields on LED's smaller than 10 micrometers.

Micro-LED and mini-LED developer Rohinni said that it developed a new placement technology for mini-LED that doubles the placement speed compared to its previous technology.

Rohinni developed a new bondhead which achieves a 100 Hz placement operation which effectively cuts in half the cost of placing mini LEDs. The technology will be deployed in the first part of 2021.